Development of Electroseismic Experimental Methods

S. S. Haines
Stanford University, Department of Geophysics, Stanford, CA

As seismic waves travel through the earth they generate a coseismic electric field via relative motion along the grain/fluid boundary. The coseismic field generates an electromagnetic disturbance when the seismic wave encounters an interface in material properties. The interface response can be measured remotely and shows virtually zero moveout. Theoretical predictions and numerical simulations predict that the interface response is produced even at very thin (~1 cm) layers. Controlled experiments will be conducted in the field to verify this prediction, and to facilitate the development of electroseismic experimental methods for application to environmental and exploration problems. By testing new data collection procedures, such as the use of electrode arrays, and the recording at each take-out of “absolute” voltage with a single electrode (relative to a common ground) rather than relative voltage measured with the commonly used dipole electrode antennae, I will seek to enhance the recorded signal relative to background noise and the coseismic field associated with surface and direct seismic waves. The development of a clear data processing procedure will permit the removal of the coseismic field from records, resulting in clearer results that can be more easily interpreted. And by quantifying the factors controlling the creation of the interface response I will enable the interpretation of the recorded response. The goal of this project is to provide a clear protocol for applying the electroseismic method to geologic problems by developing an experimental basis for the existing electroseismic theory.

AAPG Search and Discovery Article #90902©2001 AAPG Foundation Grants-in-Aid